DVD standards have been known for devices that play back stream information recorded on optical disks. On the other hand, the devices that meet with the standards for next-generation optical disks such as BD (Blu-ray Disc standards) and HD-DVD standards cannot only play back stream information thereon, but also execute programs recorded on the optical disks. The programs are recorded to provide an interactive function, and the programs are executed so that new contents (data) can be downloaded through the network and played back in synchronization with the stream information.
As an example of application programs using the network, a video-playback device has been known in which a file that updates the contents recorded on the optical disk can be downloaded (for example, refer to Patent document 1). According to Patent document 1, the network can be used, as a sub-channel, to download a language into which the contents are not dubbed. Therefore, even if there is a playback-only disk on which movie contents are recorded with Japanese voice only, English-dubbed voices are downloaded, upon playing the disk, to a local storage in the video-playback device so that videos in the optical disk can be played back in synchronization with the English-dubbed voices having been downloaded.
There is also known a video-playback device (for example, refer to Patent document 2), in which when there exist Web contents that correspond to video scenes currently being played back an icon is displayed to show that there exist online network contents, so that users are notified that the video scenes link to the Web contents. This video-playback device holds history information about connecting to Web contents in the video-playback device; and when connecting to Web contents, the device displays or hides the icon described above by referring to the connection history. When there exists less possibility for connecting the network, the network connect icon is hidden, preventing its users from unnecessarily doing access operations.    Patent Document 1: Japanese Patent Laid Open NO. 2005-159589 (page 4-5, FIG. 3)    Patent Document 2: Japanese Patent Laid Open NO. 2000-207873 (page 2-5, FIG. 4)